One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(13,21)(16,20)(18,24)(22,23)(25,26)(27,33)(28,32)(29,31)(30,35)(34,39)(36,38)(37,40) involution — undirected(1,2,5,6)(3,7,4,8)(9,10)(11,15)(12,14)(13,16)(17,19)(18,22)(20,21)(23,24)(25,27)(26,30)(28,34)(29,35)(31,33)(32,37)(36,40)(38,39)(1,3,5,4)(2,7,6,8)(10,12)(15,17)(16,20)(22,23)(26,31)(30,33)(32,38)(37,39)(1,3,5,4)(2,7,6,8)(9,11,14,19)(10,15,12,17)(13,18,21,24)(16,22,20,23)(25,26)(27,30)(28,32)(29,31)(33,35)(34,37)(36,38)(39,40)(9,12,14,10)(11,17,19,15)(13,20,21,16)(18,23,24,22)(25,27)(26,30)(28,34)(29,35)(31,33)(32,37)(36,40)(38,39)(1,4,5,3)(2,8,6,7)(9,13)(10,16)(11,18)(12,20)(14,21)(15,22)(17,23)(19,24)(25,28,29,36)(26,32,31,38)(27,34,35,40)(30,37,33,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.